In recent years, a so-called lithium ion secondary battery using as a negative electrode a carbon material is such as graphite and using as a positive electrode a lithium-containing metal oxide such as LiCoO2, which has a large capacity and is expected as a promising electrical storage device, has been used practically as the main power source for notebook computers and mobile phones. The lithium ion secondary battery is a so-called rocking chair battery such that after it is assembled, lithium ions are supplied from the lithium-containing metal oxide as the positive electrode to the negative electrode by charging the battery, and the lithium ions in the negative electrode are returned to the positive electrode by discharging the battery, and is characterized by having a high voltage, a large capacity and high safety.
Further, in recent years, attention has been paid to an electrical storage device also called a hybrid capacitor comprising a combination of storage principles of a lithium ion secondary battery and an electric double layer capacitor. As one of such devices, a capacitor has been proposed in which a negative electrode capable of absorbing and desorbing lithium ions is brought into contact with lithium metal so that lithium ions be preliminarily doped by a chemical or electrochemical method to lower the negative electrode potential, thereby to significantly increase the energy density (Patent Documents 1 to 4).
On the other hand, such an electrical storage device provided with an aprotic organic solvent electrolyte solution containing a lithium salt is being developed as a new electrical storage device (main power source and auxiliary power source) to be substituted for a lead battery for an electric car or a hybrid car to be substituted for a gasoline-powered car in an environment where environmental problems are highlighted. Particularly, due to enhancement of electrical installations and equipments for vehicles, the electrical storage device is required to have not only a higher energy density but also a high output and excellent low temperature performance.
In order to meet such requirements, it has been proposed to define the pore diameter and pore volume with respect to a negative electrode active material for an electrical storage device, for example, in Patent Document 5. Patent Document 5 discloses that among carbon materials having a similar BET specific surface area, the initial charge and discharge efficiency may substantially be different, whereby optimization of the initial efficiency by defining the BET specific surface area is difficult, and for this reason, by selecting specific ranges of the micropore amount and the mesopore amount, it is possible to accomplish a high charge and discharge efficiency. However, in spite of the object to attain a high capacity and high output, such an object has not necessarily been adequately accomplished.
Further, Patent Document 6 proposes graphite particles having the macropore volume, mesopore volume and micropore volume defined, as a negative electrode active material for a non-aqueous secondary battery. Patent Document 6 specifically defines that the graphite particles have a specific surface area of from 2.5 to 6 m2/g and a total pore volume of 0.035 cc/g, wherein the macropore volume occupies at least 40% of the total pore volume. However, this also does not necessarily sufficiently accomplish the object to attain a high capacity and high output.
Further, Patent Document 7 proposes a negative electrode active material wherein volumes of pores having pore diameters of X±α nm (3.0≦X≦10, α=1.0, such pore diameter distribution range) occupy at least 15% of the total mesopore volume. Patent Document 7 specifically discloses that a material wherein volumes of pores having pore diameters within a range of from 20 to 110 Å occupy at least 15% of the total mesopore volume, is useful as a negative electrode active material. However, this also does not adequately accomplish the object to attain a high capacity and high output.    Patent Document 1: JP-A-8-107048    Patent Document 2: JP-A-9-55342    Patent Document 3: JP-A-9-232190    Patent Document 4: PCT Publication No. WO98/033227    Patent Document 5: JP-A-2003-346801    Patent Document 6: JP-A-2000-348726    Patent Document 7: U.S. Pat. No. 6,631,073